1. Field of the Invention
The present invention relates to vehicle air bag doors.
2. Description of the Prior Art
A generally and widely known vehicle air bag door is one in which a door section is defined with a rupturable portion provided in a panel main body of an instrument panel, and the door section is opened by the activation of an air bag device provided to the bottom side of the panel main body.
Japanese Unexamined Patent Publication No. 2000-71924, for example, discloses a vehicle air bag door that is provided with a support assembly on the bottom side of a panel main body. The support assembly includes: an outer rim having an opening; a door flap that is located within the opening and is vibration welded to the bottom face of a door section; a support wall to which an air bag device is fastened; and a hinge section through which the outer rim and the door flap are connected. The support assembly is a molded resin article in which the door flap, the outer rim, the support wall and the hinge section are integrally formed. Furthermore, in this air bag door, the hinge section is formed into an approximate U-shape, and a rupturable portion is formed in a part of the panel main body overlapping the hinge section. Thus, upon activation of the air bag device, the rupturable portion is ruptured and the door flap is pivoted around the hinge section, thereby opening the door section.
On the other hand, Japanese Unexamined Patent Publication No. 2001-294114, for example, discloses another vehicle air bag door in which a hinge section is formed into a thin bellows-like shape or a thin approximate U-shape. Thus, when a door section is opened, the hinge section is extended and the door section is opened without its interference with a panel main body being caused.
In the former prior art example, since the door flap, the outer rim, the support wall and the hinge section are integrally formed, the number of components for supporting the air bag device can be reduced. However, since the hinge section is formed into an approximate U-shape and the door section is opened by pivoting the hinge section, the door section and the panel main body interfere with each other, which makes it impossible to widely open the door section. Furthermore, when the air bag device is activated, the door flap receives a pressure for deploying an air bag and pivots around the hinge section. At this time, since the support assembly is a molded resin article, an outer portion of the hinge section (i.e., a portion thereof having a larger radius of rotation) might be broken due to reception of an extension force in the direction in which the door flap is pivoted (turned). Therefore, the thickness of the hinge section, for example, must particularly be taken into consideration.
On the other hand, in the latter prior art example, the hinge section is formed into a thin bellows-like shape. Thus, when the door section is opened, a door flap is pivoted while the bellows-like hinge section is being extended. However, the door flap violently collides against a door-section-side edge of the panel main body, and therefore, the hinge section might be deformed or broken. In addition, since the hinge section is thin, the door section might be bent downward and broken when a load is applied to an instrument panel from above. Furthermore, such a problem might similarly occur in the case where the hinge section is formed into a thin U-shape.